TITLE: Mindfulness Training for Weight Loss in Obese Adults: A Review of the Clinical Evidence and Guidelines

Transcription

1 TITLE: Mindfulness Training for Weight Loss in Obese Adults: A Review of the Clinical Evidence and Guidelines DATE: 12 January 2012 CONTEXT AND POLICY ISSUES Obesity is typically defined as a body mass index (BMI) of over 30 kg/m 2. Individuals who are obese have an increased risk of a variety of chronic diseases including type 2 diabetes mellitus, cardiovascular disease, hypertension, and liver disease. 1 The number of people who are obese has been increasing worldwide and it is now considered to be a global epidemic. 2 The World Health Organization estimated that, in 2005, 9.8% of the world s population was obese. 2 A 2007 Canadian Community Health Survey indicated that the self-reported rate of obesity in adults was 17%; however, researchers from the Public Health Agency of Canada suggested that actual rate of may be closer to 25%. 1 Obesity has been shown to have significant cost implications and, in 2005, the total cost associated with chronic conditions related to obesity was estimated to be $4.3 billion. 1 Obesity has been recognized as a complex problem that is influenced by behavioural, physiological, environmental, social, and economic factors. 2,3 Interventions that seek to modify the dietary and exercise behaviour of obese individuals often fail to achieve long-term weight reduction. Mind-body therapies have been proposed as a possible weight-loss intervention for obese individuals. The National Center for Complementary and Alternative Medicine in the United States describes mind-body therapies as interventions which focus on the brain, mind, body, and behaviours with the intent to use the mind to affect physical function and promote health. 4 The objective of this review is to summarize the clinical effectiveness and guidelines for the use of mindfulness training for the treatment of obesity in adults. RESEARCH QUESTIONS 1. What is the clinical effectiveness of mindfulness training for weight management in obese adults? 2. What are the evidence-based guidelines regarding the use of mindfulness training for weight management in obese adults? Disclaimer: The Rapid Response Service is an information service for those involved in planning and providing health care in Canada. Rapid responses are based on a limited literature search and are not comprehensive, systematic reviews. The intent is to provide a list of sources and a summary of the best evidence on the topic that CADTH could identify using all reasonable efforts within the time allowed. Rapid responses should be considered along with other types of information and health care considerations. The information included in this response is not intended to replace professional medical advice, nor should it be construed as a recommendation for or against the use of a particular health technology. Readers are also cautioned that a lack of good quality evidence does not necessarily mean a lack of effectiveness particularly in the case of new and emerging health technologies, for which little information can be found, but which may in future prove to be effective. While CADTH has taken care in the preparation of the report to ensure that its contents are accurate, complete and up to date, CADTH does not make any guarantee to that effect. CADTH is not liable for any loss or damages resulting from use of the information in the report. Copyright: This report contains CADTH copyright material. It may be copied and used for non-commercial purposes, provided that attribution is given to CADTH. Links: This report may contain links to other information available on the websites of third parties on the Internet. CADTH does not have control over the content of such sites. Use of third party sites is governed by the owners own terms and conditions.

2 KEY MESSAGE RCTs failed to consistently demonstrate statistically significant or clinically-meaningful weightloss with mindfulness training. Two evidence-based guidelines recommend the use of behavioural modification therapy for the management of obesity; however, neither guideline specifically addressed any particular mindfulness interventions. METHODS Literature Search Strategy A limited literature search was conducted on key resources including MEDLINE, EMBASE, PsycINFO, PubMed, The Cochrane Library (2011, Issue 11), University of York Centre for Reviews and Dissemination (CRD) databases, Canadian and abbreviated list of major international health technology agencies, as well as a focused Internet search. No filters were applied to limit the retrieval by study type. Where possible, retrieval was limited to the human population. The search was also limited to English language documents published between Jan 1, 2006 and Dec 1, Selection Criteria and Methods One reviewer screened the titles and abstracts of the retrieved publications and evaluated the full-text publications for the final article selection according to criteria presented in Table 1. Table 1: Selection Criteria Population Overweight or obese adults Intervention Comparator Outcomes Study Designs Mindfulness training Any Effectiveness in reducing body weight Effectiveness in maintaining body weight Clinical practice guidelines Health technology assessments, systematic reviews and meta-analyses, Randomized controlled trials, evidence-based guidelines Exclusion Criteria Studies meeting any of the following criteria were excluded: non-randomized primary studies, case series, case reports, non-english language publications. Critical Appraisal of Individual Studies Critical appraisal of the included studies was performed according to study design. Appraisal of full-text publications for primary studies was performed using the criteria described by Downs and Black. 5 Clinical practice guidelines were assessed using the Appraisal of Guidelines for Research and Evaluation (AGREE) criteria. 6 Numeric scores were not calculated. Instead, the Mindfulness Training for Weight Loss 2

3 strengths and limitations of each guideline were described. No health technology assessments or systematic reviews were identified for critical appraisal. SUMMARY OF EVIDENCE Quantity of Research Available A total of 229 citations were retrieved from the literature search. The abstracts for these reports were reviewed and 14 studies that could potentially fulfill the selection criteria were identified for further screening. Three additional references were retrieved from the grey literature. The screening process resulted in the selection of seven reports for inclusion in the present review. A summary of the screening results is provided in Appendix 1. Five reports 7-11 described four unique RCTs and two reports were evidence-based guidelines. 12,13 Summary of Study Characteristics A summary of the characteristics of the included studies is provided in Appendix 2 and a detailed description of study interventions is provided in Appendix 5. The mind-body interventions included the following: a mindfulness intervention for stress eating (10 sessions), 7 relaxation response training ( 10 sessions), 9 mindfulness and acceptance-based (one session), 10 and mindfulness-based weight loss training (four sessions). 11 Three of the RCTs 7,9,11 included only women and one RCT 10 included 90% women. The mean BMI of study participants ranged from 31 kg/m 2 to 35 kg/m 2. Three RCTs 9-11 were completely open-label and one was single blinded (assessors). 7 All studies used a parallel-group design and sample sizes ranged from 47 7 to Follow-up was conducted at three months, 10 four months, 7 six months, 11 one year, 9 and two years. 8 Summary of Critical Appraisal Randomized controlled trials All of the studies had a clearly stated objective with a well-described protocol and all reported the study eligibility criteria. The study populations were either 100% or 90% women which may limit the generalizability of the findings as it is unclear if the results would be replicated in overweight or obese men. Common limitations with the available evidence included poor reporting of randomization methods 9-11 and a lack of clarity regarding allocation concealment The interventions were unblinded in all studies. Given the complexity of the interventions in these studies, blinding of participants and clinical staff would likely be unfeasible; however, the lack of blinding remains an important source of potential bias for the included studies. Three RCTs 7,10,11 reported the baseline characteristics of participants and all were similar between the different treatment groups. One study did not present the demographic and baseline characteristics individually for each treatment group. 9 Three of the RCTs 7,10,11 had a high proportion of participants complete the study (range 82% to 100%) and one 9 had a high proportion of participants who were lost to follow-up (37% at one year and 48% at two years). Two studies 9,10 reported sample size calculations. Evidence-based guidelines Both of the evidenced-based guidelines 12,13 were of good quality and were formulated with a rigorous methodology (Appendix 4). Key limitations of the two guidelines were poor reporting of Mindfulness Training for Weight Loss 3

4 the methods and search results of the systematic review(s) and a lack of specificity regarding the intervention(s) that should be considered when applying the recommendations. Summary of Findings Mind-body techniques combined with group sessions One RCT compared the effects of three non-dieting interventions in overweight women (N = 225). The participants were randomized to one of the following intervention groups: 1) group non-dieting program based on relaxation response training; 2) group non-dieting program; or 3) a mail-delivered non-dieting program. Participants in the group sessions attended a two hour session every week for the first 10 weeks and then every two to four weeks for next eight months. The group program which included the relaxation component was based on a protocol from the Harvard Mind/Body Medical Institute 14,15 and included instruction in the following mindbody techniques: meditation mindfulness, progressive muscle relaxation, abdominal breathing, hatha yoga, and visualization. Follow-up was reported at 12 months by Katzer et al (2008) 9 and at 24 months by Hawley et al (2008). 8 There were no statistically significant changes from baseline in the mean body weight in any of the three treatment groups at 12 and 24 months follow-up (Table 2). Katzer et al (2008) 9 reported that there was a statistically significant difference favouring the treatment arm that received the instruction in mind-body techniques compared with the arm which only participated in group sessions (P < 0.05); however, there was no difference in comparison with the group which received the mail-delivered program. Table 2: Summary of findings from Katzer and Hawley Intervention Body Weight at BL (kg) from BL Body Weight (kg) Mean (SD) Within Group Comparison P value Mean (SD) 12 months 24 months 12 months 24 months Group NDP + MBT 95.5 (15.7) -0.9 (5.9) -1.8 (6.2) Group NDP 93.2 (14.7) 1.2 (3.9) -0.4 (5.8) Mail-delivered NDP 93.9 (17.3) -0.3 (4.9) -2.0 (8.6) =change; BL=baseline; MBT=mind-body techniques; NDP=non-dieting program; SD=standard deviation Mindfulness intervention for stress eating Daubenmier et al (2011) 7 conducted an RCT comparing a mindfulness intervention for stress eating against waiting list control in overweight and obese women (N = 47). The authors described the intervention as involving components from mindfulness-based stress reduction, mindfulness-based cognitive therapy, and mindfulness-based eating awareness training. After four months, there was no statistically significant difference between the two groups with respect to the change from baseline in body weight. The authors conducted subgroup analyses and reported that obese participants in the intervention group maintained their body throughout the trial ( 0.4 ± 3.5 kg; P = 0.70) and those in the control group gained weight (1.7 ± 1.5 kg, P = 0.01); however, there was still no statistically significant difference between the two groups (P = 0.12). A subgroup analysis focusing on the overweight participants demonstrated that there was no statistically significant difference between the two groups (P = 0.47). Mindfulness Training for Weight Loss 4

5 Table 3: Summary of findings from Daubenmier Analysis T C (95% CI) P value Body weight - ITT 0.40 kg ( 1.8, 1.0) P = 0.56 Body weight - PP 0.64 kg ( 2.3, 1.0) P = 0.45 C=control; CI=confidence interval; ITT=intention to treat; PP=per protocol; T=treatment One-day mindfulness and acceptance-based workshop Lillis et al (2009) 10 conducted an RCT to compare the effectiveness of attending a one-day mindfulness and acceptance-based workshop versus a waiting list for patients who had completed at least 6 months of a weight loss program (N = 84). The workshop targeted obesityrelated stigma and psychological distress and follow-up was conducted after three months. The patients in the intervention group showed greater improvement in percentage change in body weight (-1.5% vs. 0.3%) and BMI (-0.4 kg/m 2 vs kg/m 2 ) compared to the waiting list control group (both p < 0.01). The authors concluded that their results provide preliminary evidence in support of the intervention and that more study is warranted in this area. Addition of mindfulness-based interventions to existing weight loss plans Tapper et al (2009) 11 conducted an RCT to evaluate the efficacy of adding a mindfulness-based weight loss intervention to the weight loss plans of women (N = 62). The control group received no mindfulness-based intervention and the participants continued with their own weight loss plan. The intervention consisted of four two-hour workshops addressing issues such as values, cognitive diffusion, controlling feelings, acceptance, self-awareness, mindfulness, and committed action. Follow-up was conducted after six months and there was no statistically significant difference in weight loss between the two groups. The authors conducted a subgroup analysis by removing seven participants who reportedly did not apply the workshop principles. With these patients removed, there was statistically significant improvement in the BMI of the intervention group compared to the control group (P < 0.05). These results should be interpreted with caution as it is unclear if this subgroup was post-hoc or pre-specified. In addition, there were no adjustments made for multiple comparisons. Evidence-based guidelines The literature search identified two evidence-based guidelines that offer recommendations regarding the use of behavioural therapy for the treatment obesity. Neither guideline specified any particular behavioural therapies in their recommendations. The 2006 Canadian clinical practice guidelines on the management and prevention of obesity in adults and children included a section on the use of behaviour therapy. 12 The guideline states that each recommendation is evidence-based, involved a systematic review of the literature, and represents a consensus of the expert review panel. The guideline specifies the following three recommendations with respect to behavioural therapies for the treatment of obesity: 1. We suggest that individuals willing to participate in weight management programs be provided with education and support in behaviour modification techniques as an adjunct to other interventions (Grade B; level 2) 2. We recommend comprehensive lifestyle interventions (combining behaviour modification techniques, cognitive behaviour therapy, activity enhancement and dietary counseling) for all obese adults (Grade A; level 1) Mindfulness Training for Weight Loss 5

6 3. When treating obesity in children, we suggest using family-oriented behaviour therapy (Grade B; level 1) The strength of each recommendation refers to the following: Grade A - strong recommendation where the benefits clearly outweigh risks (or vice versa); Grade B - intermediate recommendation where it is unclear whether benefits outweigh risks. The level of evidence refers to the following: level 1 - RCTs (or meta-analyses) without important limitations; level 2 - RCTs (or meta-analyses) with important limitations and/or observational studies with overwhelming evidence. The Scottish Intercollegiate Guidelines Network (SIGN) has also published an evidence-based guideline for the management of obesity. 13 The section regarding weight management programmes and support for weight loss maintenance in adults addresses the use of behavioural therapies and recommends the following: Weight management programmes should include physical activity, dietary change and behavioural components (Grade A). The Grade A level of evidence indicates that the recommendation is supported by evidence from at least one meta-analysis, systematic review, or RCT with a low risk of bias and is directly applicable to the target population. Limitations There were no systematic reviews and only four RCTs identified in this review; therefore, there is limited evidence available to address the research questions. Each of the RCTs investigated a different mindfulness intervention so there is no replication of findings. Three of the RCTs had a small sample size and a short duration, and the longer term RCT was limited by a high proportion of participants who were lost to follow-up. The RCT evidence is also limited by the use of multiple mindfulness interventions in a single treatment group which makes it difficult to determine which components contributed to the effect. The most extreme example is the study by Daubenmier et al (2011) 7 where the intervention involved components from mindfulnessbased stress reduction, mindfulness-based cognitive therapy, and mindfulness-based eating awareness training. The studies all enrolled at least 90% women which may limit the generalizability of these findings to overweight and obese men. Further study would be required to determine how men would respond to mind-body therapies for weight management. The two evidence-based guidelines lacked specific information regarding which behavioural interventions should be considered for weight management. CONCLUSIONS AND IMPLICATIONS FOR DECISION OR POLICY MAKING: The four open-label RCTs identified in this review had limited sample sizes and failed to consistently demonstrate statistically significant weight-loss with mindfulness training. Furthermore, the weight-loss reported for participants in the mindfulness groups was small (i.e., <2 kg) and of uncertain clinical significance. Larger studies with a longer duration would be required to accurately assess the effects of mindfulness training for managing obesity. In addition, the evidence identified in this review was restricted to obese women; therefore, the effectiveness of mindfulness training in obese men is uncertain. Two evidence-based guidelines recommend the use of behavioural modification therapy for the management of obesity; however, neither guideline specifically addressed any particular mindfulness interventions. Mindfulness Training for Weight Loss 6

7 PREPARED BY: Canadian Agency for Drugs and Technologies in Health Tel: Mindfulness Training for Weight Loss 7

8 REFERENCES 1. Public Health Agency of Canada. Obesity in Canada: snapshot [Internet]. Ottawa: The Agency; [cited 2012 Jan 5]. Available from: 2. Caballero B. The global epidemic of obesity: an overview. Epidemiol Rev [Internet] [cited 2012 Jan 5];29:1-5. Available from: 3. Koithan M. Mind-body solutions for obesity. J Nurse Pract [Internet] [cited 2011 Dec 14];5(7): Available from: 4. National Center for Complementary and Alternative Medicine (NCCAM) [Internet]. Bethesda (MD): National Institutes of Health. What is complementary and alternative medicine? Mind and body medicine; 2008 Oct [cited 2012 Jan 5; updated 2011 Jul]. Available from: 5. Downs SH, Black N. The feasibility of creating a checklist for the assessment of the methodological quality both of randomised and non-randomised studies of health care interventions. J Epidemiol Community Health Jun;52(6): The AGREE Collaboration. Appraisal of guidelines for research and evaluation (AGREE) instrument [Internet]. London: The AGREE research trust; 2001 Sep. [cited 2011 Dec 22]. Available from: 7. Daubenmier J, Kristeller J, Hecht FM, Maninger N, Kuwata M, Jhaveri K, et al. Mindfulness intervention for stress eating to reduce cortisol and abdominal fat among overweight and obese women: an exploratory randomized controlled study. J Obes [Internet] [cited 2011 Dec 22];2011: Available from: 8. Hawley G, Horwath C, Gray A, Bradshaw A, Katzer L, Joyce J, et al. Sustainability of health and lifestyle improvements following a non-dieting randomised trial in overweight women. Prev Med Dec;47(6): Katzer L, Bradshaw AJ, Horwath CC, Gray AR, O'Brien S, Joyce J. Evaluation of a "nondieting" stress reduction program for overweight women: a randomized trial. Am J Health Promot Mar;22(4): Lillis J, Hayes SC, Bunting K, Masuda A. Teaching acceptance and mindfulness to improve the lives of the obese: a preliminary test of a theoretical model. Ann Behav Med. 2009;37(1): Tapper K, Shaw C, Ilsley J, Hill AJ, Bond FW, Moore L. Exploratory randomised controlled trial of a mindfulness-based weight loss intervention for women. Appetite. 2009;52(2): Lau DC, Douketis JD, Morrison KM, Hramiak IM, Sharma AM, Ur E, et al Canadian clinical practice guidelines on the management and prevention of obesity in adults and Mindfulness Training for Weight Loss 8

9 children. CMAJ [Internet] Apr 10 [cited 2011 Dec 22];176(8 suppl):online Available from: Scottish Intercollegiate Guidelines Network. Management of obesity: a national clinical guideline [Internet]. Edinburgh: SIGN; 2010 Feb. [cited 2011 Dec 22]. Available from: Nakao M, Myers P, Fricchione G, Zuttermeister PC, Barsky AJ, Benson H. Somatization and symptom reduction through a behavioral medicine intervention in a mind/body medicine clinic. Behav Med. 2001;26(4): Nakao M, Fricchione G, Myers P, Zuttermeister PC, Baim M, Mandle CL, et al. Anxiety is a good indicator for somatic symptom reduction through behavioral medicine intervention in a mind/body medicine clinic. Psychother Psychosom Jan;70(1):50-7. Mindfulness Training for Weight Loss 9

10 Appendix 1: Selection of Included Studies 229 citations identified from electronic literature search and screened 215 citations excluded 14 potentially relevant articles retrieved for scrutiny (full text, if available) 3 potentially relevant reports retrieved from other sources (grey literature, hand search) 17 potentially relevant reports 10 reports excluded: -irrelevant intervention (5) -irrelevant outcomes (1) -irrelevant population (1) -review article (1) -comment (1) -review protocol (1) 7 reports included in review Mindfulness Training for Weight Loss 10

11 Appendix 2: Characteristics of the Included Randomized Controlled Trials Author, Year, Country Daubenmier, USA Description Comparators Endpoints Population F/U at 4 month Single-blind Parallel-group Single center N = 47 Mindfulness intervention for stress eating Waiting list (control) Mindfulness Stress Anxiety Body weight Overweight women Mean BMI = 31 Lillis USA F/U at 3 months Open label Parallel-group Single center N = 87 Mindfulness and acceptance-based workshop (1 day) Waiting list (control) Body weight BMI Quality of life Mental health Individuals who had completed 6 months of an weight loss program Mean BMI = 33 Tapper United Kingdom F/U at 6 months Open label Single center Parallel group N = 62 Mindfulness-based weight loss training + Participants own weight loss plans Participants own weight loss plans BMI Physical activity Mental health Eating behaviour Women attempting to lose weight Mean BMI = 32 Hawley Katzer New Zealand F/U at 12 & 24 months Open label Parallel group N = 225 Group NDP + MBT Group NDP Mail-delivered NDP Body weight BMI Psychological distress Medical symptoms Eating behaviour Blood pressure Overweight women Mean BMI = 35 BMI=body mass index (kg/m 2 ); CBT=cognitive behavioural therapy; F/U=follow-up; NDP=non-dieting program; PTSD=post-traumatic stress disorder; MBSR=mindfulness-based stress reduction; MBT=mind-body techniques; PMR=progressive muscle relaxation Mindfulness Training for Weight Loss 11

12 Appendix 3: Critical Appraisal of Randomized Controlled Trials Author, Year Strengths Limitations Daubenmier Objective and methods were clearly stated Eligibility criteria was clearly stated Interventions were clearly described Single blinded (nurses) Methods of randomization were appropriate and well-reported Randomization was stratified by key baseline characteristics (e.g., BMI) Baseline characteristics were well described and were similar between the two groups Compliance was systematically assessed 85% of participants completed the trial 100% of participants were women (limited generalizability for men) No sample size calculations provided Limited sample size (N = 47) Included both an ITT and PP analysis; however, the ITT analysis was not based on all randomized patients Multiple statistical tests performed without correction for multiple comparisons Lillis Tapper Hawley Katzer Objective and methods were clearly stated Eligibility criteria was clearly stated Interventions was clearly described Sample size calculation provided Baseline characteristics were similar between the two groups with the exception of previous weight-loss success (difference was addressed using an adjusted analysis) Patient disposition was well reported No participants who received the intervention and no one in the control group was lost to follow-up Objective and methods were clearly stated Eligibility criteria was clearly stated Methods of randomization were provided Baseline characteristics were similar between the two groups Patient disposition was well reported 84% and 81% of participants completed the trial for the intervention and control groups, respectively Compliance was reported for the intervention group based on workshop attendance. Included an ITT analysis based on all randomized participants Objective and methods were clearly stated Eligibility criteria was clearly stated Interventions were clearly described Sample size calculation provided Methods of randomization were provided 99% of participants were included in the ITT analysis Treatments were open-label Unclear if randomization was adequately concealed from the investigators 90% of participants were women (limited generalizability for men) Treatments were open-label Unclear if randomization was adequately concealed from the investigators No sample size calculation provided 100% of participants were women (limited generalizability for men) Treatments were open-label 37% and 48% of participants were lost to follow-up at one and two years, respectively 100% of participants were women (limited generalizability for men) Unclear if randomization was adequately concealed Demographic and baseline characteristics were not presented for the groups individually BMI=body mass index; ITT=intention to treat; PP=per protocol Mindfulness Training for Weight Loss 12

13 Appendix 4: Critical Appraisal of Evidence-based Guidelines Author, Year Strengths Limitations Lau The objectives of the guideline are specifically described The population to whom the guideline is meant to apply is specifically described Individuals from relevant professional groups were included in development of the guideline group The target users of the guideline were clearly defined Systematic methods were used to search for evidence The methods used for formulating the recommendations were clearly described The strength of evidence is clearly described Unclear if patient input was considered in the development process Research questions were not clearly stated Methods and search results for the systematic review were poorly reported The recommendations lack specificity regarding the intervention(s) that should be considered SIGN The objectives of the guideline are specifically described Research questions were clearly stated The population to whom the guideline is meant to apply is specifically described Individuals from relevant professional groups were included in development of the guideline group Patients were involved throughout the guideline development process The target users of the guideline were clearly defined Systematic methods were used to search for evidence The methods used for formulating the recommendations were clearly described The strength of evidence is clearly described Methods and search results for the systematic review were poorly reported The recommendations lack specificity regarding the intervention(s) that should be considered Mindfulness Training for Weight Loss 13

14 Appendix 5: Detailed Description of Study Interventions Author, year Interventions Key Findings Daubenmier, Mindfulness Intervention Nine 2.5-hour classes and one 7-hour silent day of guided meditation practice after class 6. Classes were held on a weekly basis on the weekend. Participants were instructed in the body scan, mindful yoga stretches, sitting and loving kindness meditations as taught in MBSR, and the 3 minute breathing space as taught in MBCT. Participants were also led through guided meditations as a way to introduce mindful eating practices of paying attention to physical sensations of hunger, stomach fullness, taste satisfaction, and food cravings; identification of emotional and eating triggers; self-acceptance; and inner wisdom. Meditations on awareness of negative emotions in general and loving kindness and forgiveness towards others were included as supplemental meditations. Each session opened with a mindfulness practice followed by a discussion of the practice and review of progress and challenges over the previous week, and then guided meditations and discussions were used to introduce new eating or emotional awareness practices. On the retreat day, participants entered into silence to practice the meditations they had been taught and had a potluck meal to practice mindful eating skills. Participants were encouraged to engage in daily home assignments that included up to 30 minutes per day of formal mindfulness practices 6 days per week and mindful practices before and during meals. (page 3) No statistically significant difference between the two groups with respect to the change from baseline in body weight Waiting-list (control group) To provide guidelines for healthy eating and exercise during the intervention and to control the effects of such information on study outcomes, both groups participated in a 2-hour nutrition and exercise information session aimed at moderate weight loss midway through the intervention, in which mindfulness was not discussed. (page 3) Lillis Mindfulness Intervention Participants were given a 1 day, 6 hour workshop utilizing exercises and material that have been shown to be helpful in similar ACT protocols. Each workshop used a structured sequence of lecture and exercises. Two workshop leaders led every group. The specific methods used taught acceptance, mindfulness, and defusion skills as applied to difficult thoughts, feelings, and bodily sensations. Weightrelated stigmatizing thoughts and distress were the primary focus. The workshop also sought to clarify life values, especially those related to health and relationships, identify barriers to their implementation, and to foster behavioral commitments related to life values. A general ACT workbook was also distributed to participants to encourage further implementation of the methods presented. (page 61) Waiting-list (control) Did not receive the intervention. Patients in the intervention group showed greater improvement in percentage change in body weight (-1.5% vs. 0.3%) and BMI (-0.4 kg/m 2 vs kg/m 2 ) compared to the waiting list control group (both P < 0.01) Mindfulness Training for Weight Loss 14

15 Author, year Interventions Key Findings Tapper Mindfulness Intervention Key intervention components were (a) values, to enhance motivation, (b) cognitive defusion, to help break links between food- and exerciserelated thoughts and behaviour, and (c) acceptance, to help the individual tolerate negative feelings. The intervention was delivered via a series of 3 workshops conducted over 3 consecutive weeks with a fourth follow-up session taking place approximately 3 months later. Each session lasted 2 hours and included a powerpoint presentation and explanation of key concepts using metaphors, exercises and pen and paper tasks. Questions were encouraged during the session to ensure concepts were understood. Participants were also asked to complete a series of homework exercises in between each session. A manual was provided to accompany the workshops. This included details of key concepts and exercises, forms for pen and paper-based tasks and details of homework. Participants also received a CD containing the four eyes-closed exercises: Leaves on a Stream, Giving Feelings a Form, The Tin Can Monster Exercise and Being Where You Are. This was designed to support participants practice at home. (page ) No statistically significant difference in weight loss between the two groups. Participants own weight loss plans (control group) Asked to continue their weight loss attempt as normal. No further information was provided to control participants but they were given the opportunity to attend a 1 day weight loss workshop at the end of the study. Hawley Katzer Mindfulness Intervention Weekly two-hour sessions during the initial 10 weeks of the intervention, followed over the next 8 months by 12 two-hour group sessions. The Intervention was modeled on the Harvard Mind/Body Medical Institute Medical Symptom Reduction Program. Each session included intensive instruction and practice using various mindbody techniques including: progressive muscle relaxation, abdominal breathing, meditation, hatha yoga, visualization, and mindfulness. Group sessions were conducted by a psychotherapist trained in and experienced with mind-body techniques and a nutritionist. The nutritionist had undertaken training in mind-body medicine with the Harvard Mind/Body Medical Institute. (page 595) 8 Group non-dieting program (control) Weekly two-hour sessions during the initial 10 weeks of the intervention, followed over the next 8 months by 12 two-hour group sessions. The intervention involved a greater focus on nutrition and physical activity than the mindfulness intervention. Participants were taught to use goal-setting, self-monitoring (diary) and stimulus control strategies in order to develop healthy non-dieting, eating and activity behaviors. Sessions were conducted by an experienced dietitian, with a psychotherapist and a lifestyle activity consultant brought in for specific topics. (page 595) 8 No statistically significant changes in mean body weight in any treatment group Mail-delivered non-dieting program (control) A 10-week mail-delivered, self-directed program with a focus on nutrition and physical activity. Materials included a reflective diary (for goal-setting and monitoring), a variety of recipe leaflets, shopping guides and physical activity brochures. Participants received program material for first 10 weeks, followed by monthly newsletters for the remaining 8 months. (page 595) 8 ACT=acceptance and commitment therapy; BMI=body mass index; MBSR=mindfulness-based stress reduction; MBCT=Mindfulness-Based Cognitive Therapy Mindfulness Training for Weight Loss 15